KR101528841B1 - Apparatus and method for searching broadcast channel in wireless communication system - Google Patents

Abstract

A method and apparatus for searching for a broadcast channel in a wireless communication system, the method comprising: performing a channel search on all broadcast channels at power-on; Generating and storing a list including parameter information and performing a channel search on channel parameters included in the stored list when a channel search event is generated, The service quality can be improved by minimizing the waiting time of the user, and the actual broadcast viewing time can be increased compared to the limited power.

Broadcast reception, channel search, transmission mode, scan mode

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for searching for a broadcast channel in a wireless communication system,

The present invention relates to a method and apparatus for searching a broadcast channel in a wireless communication system, and more particularly, to a method and apparatus for searching for a transmission mode and a parameter for each channel stored in a digital multimedia broadcasting receiver to reduce a channel search time.

In recent years, Digital Multimedia Broadcasting has become possible not only in the existing voice radio service, but also in data transmission and multimedia services. The digital multimedia broadcasting is robust against noise and distortion on a transmission channel, has a high transmission efficiency, and has various merits of enabling various multimedia services. Thus, the digital multimedia broadcasting is equipped with the digital multimedia broadcasting receiver in various electronic devices.

In general, broadcasting companies transmit broadcasting signals by applying various transmission parameters according to a transmission standard and a channel state. Therefore, the broadcasting receiver repeatedly performs channel searching while changing all parameters that can be transmitted for all channels.

In particular, recently, a digital broadcast receiver using an Orthogonal Frequency Division Multiplexing (OFDM) scheme, such as Integrated Services Digital Broadcasting (ISDB) -T, detects a transmission mode for each channel while changing each channel, And receives broadcasting data by acquiring synchronization for each channel using effective symbols and guard intervals of different lengths according to each transmission mode.

FIG. 1 shows an operation procedure of a digital broadcast receiver according to the related art.

Referring to FIG. 1, in step 101, when a broadcast viewing event occurs in step 101, the digital broadcasting receiver synchronizes the selected channel in step 103 and receives a broadcast signal. In step 105, the digital broadcasting receiver compares the intensity of the received signal with a preset threshold value to determine whether the intensity of the received signal is strong enough to watch the broadcast. If the received signal strength is an intensity of a degree that enables broadcast viewing, the digital broadcasting receiver proceeds to step 111 and displays a broadcast. If the received signal strength is an intensity that is impossible to view a broadcast, And performs scanning for all channels to search for a channel in which a broadcast signal exists. The digital broadcasting receiver updates the channel list using the searched channels in step 109, displays the searched channel list in step 111, and terminates the algorithm according to the present invention.

In the transmission standard of the OFDM system such as the ISDB-T, various transmission modes are defined according to the frequency band and the reception area. The parameters of each transmission mode include the number of subcarriers, the frame length, the guard interval length, the effective symbol length, Length and so on. That is, in the digital broadcasting transmitter, the broadcasting signal is transmitted by applying the various transmission parameters to each channel, so that the digital broadcasting receiver repeatedly searches all the parameters one by one for each channel. In the digital broadcasting system in which the number of channels is considerably large, the channel searching method as described above has a problem in that a considerable time is required for channel searching.

Therefore, in order to reduce the channel search time as described above, a channel list for each domain is previously stored in the digital broadcast receiver, and a channel search is performed by referring to the channel list. However, in the case where a situation other than the pre-stored channel list occurs, such as when a broadcast service area is changed or a broadcast channel number is changed, the modified broadcast channel is not received It becomes impossible to do so.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method and apparatus for searching for a broadcast channel in a wireless communication system.

It is another object of the present invention to provide a method and apparatus of a digital multimedia broadcasting receiver that performs searching only for transmission modes and parameters for each channel previously stored in a wireless communication system.

It is still another object of the present invention to provide a method and apparatus for performing a search for all channels or a search for a pre-stored channel in a wireless communication system according to a channel reception status.

It is still another object of the present invention to provide a method and apparatus for updating pre-stored channel information in a wireless communication system according to channel reception conditions.

According to a first aspect of the present invention, there is provided a method of searching for a broadcast channel in a digital multimedia broadcasting (DMB) receiver, the method comprising: performing channel search for all broadcast channels when power is turned on; Generating and storing a channel list including at least one of a transmission mode and transmission parameter information corresponding to the searched broadcast channel; and generating, when a channel search event is generated, Mode and a transmission parameter based on at least one of the mode and the transmission parameter.

According to a second aspect of the present invention, there is provided a device for searching for a broadcast channel in a digital multimedia broadcasting (DMB) receiver, the device comprising: a controller for controlling a function of performing channel search on all broadcast channels at power- Performs a channel search for all the broadcast channels under the control of the control unit and generates a channel list including at least one of a transmission mode and transmission parameter information corresponding to the broadcasting channel together with the broadcasting channel searched by the channel searching A communication module for performing channel search based on at least one of a transmission mode and transmission parameters for a broadcast channel included in the channel list when a channel search event is generated; .

The present invention provides a digital multimedia broadcasting receiver of a wireless communication system, which performs a search on all channels, stores a channel on which a broadcast signal is received, performs a channel search only on the stored channel parameters when a channel search event is generated, It is possible to save the time required for channel search and to provide a fast and stable channel search service because broadcasting operators can instantaneously match transmission modes and parameter values even in a service environment in which broadcasting signals are transmitted with different transmission efficiencies according to the quality of contents There is an effect that can be provided. Also, the present invention can reduce the time required for channel search, minimize the waiting time of the user, improve the service quality, and increase the actual broadcast viewing time as compared with the limited power of the digital broadcasting receiver.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, a method and apparatus for performing a search for all channels or performing a search for a pre-stored channel according to a channel reception status in a digital broadcast receiver of a wireless communication system will be described. Hereinafter, the digital broadcast receiver according to the present invention includes a portable terminal, a mobile communication terminal, and an electronic apparatus capable of receiving digital broadcasting.

2 shows a block diagram of a digital broadcast receiver according to the present invention. The digital broadcasting receiver includes a communication module 200, a control unit 210, a memory 220, a display unit 230, and an input unit 240. The communication module 200 Includes a broadcast reception chip 202 and the control unit 210 includes a channel search control unit 212 and the memory 220 includes a channel list storage unit 222.

Referring to FIG. 2, the communication module 200 lowers a frequency of a high-frequency signal received through an antenna, decodes the frequency, and provides the decoded signal to the controller 210. In particular, the communication module 200 searches for a broadcast channel under the control of the controller 200 including the broadcast receiving chip 202, processes a signal received from the searched broadcast channel, and provides the signal to the controller 210 . That is, under the control of the controller 200, the broadcast reception chip 202 changes transmission modes and transmission parameters for all channels or channels included in the channel list stored in the memory 230, Search for an existing channel.

The broadcast receiving chip 202 searches all the channels at the time of performing the power-on process of the terminal according to the control of the controller 210, and generates a channel in which a broadcasting signal exists, a transmission mode for the broadcasting signal, And provides the list to the controller 210. At this time, the broadcast reception chip 202 transmits a Guard Interval Process (GI_PROC) to each channel in accordance with a Fast Fourier Transform (FFT) size and a guard interval length of each of the plurality of transmission modes And determines the transmission mode of the corresponding channel by selecting a transmission mode having the largest maximum value of the correlation value. At this time, the broadcast receiving chip 202 extracts timing information from the position of the maximum value of the correlation value to perform rough timing acquisition.

Also, under the control of the controller 210, the broadcast receiving chip 202 receives the broadcast signal using the transmission mode and parameter information previously selected for the channel selected in the initial broadcast receiving step. Here, the pre-selected channel may be a channel set in the digital broadcast receiver, a channel selected by the user, or a channel previously viewed by the user. The broadcast receiving chip 202 periodically searches for the searched channel in the idle state of the digital broadcasting receiver under the control of the controller 210 and updates the channel list. Here, the broadcast receiving chip 202 is provided with a transmission mode for each channel and each channel in which a broadcasting signal is present under the control of the controller 200, and when searching for the corresponding channel, First, channel search is performed.

The control unit 210 controls and processes the overall operation of the digital broadcasting receiver and includes the channel search controller 212 according to the present invention to receive the broadcast reception chip 202 included in the communication module 200 And controls and processes a function for searching for a broadcast channel.

The channel search controller 212 controls the broadcast receiver chip 202 to perform full scanning when the digital broadcast receiver is powered on. That is, the channel search controller 212 controls the broadcast reception chip 202 to search for a transmission mode of each channel while changing all of the transmission modes for all channels at the power-on process. Here, the full scanning when performing the power-on process includes a time for performing the full scanning at a boot process time for turning on the power, thereby reducing the burden on the user of the full scanning. At this time, if the booting process is completed but the full scanning process is not completed, the channel search controller 212 controls the full scanning process to be performed until the key interrupt is generated by the user, If the key interrupt is generated by the user after completion of the process, the full scanning process is stopped.

The channel search controller 212 receives a channel in which a broadcast signal exists and a channel list indicating information on transmission modes and parameters of each channel from the broadcast reception chip 202 and stores the channel list in the memory 220. Then, the channel search controller 212 periodically scans the channels included in the channel list in the idle state of the digital broadcasting receiver to update the channel list. Also, the channel search controller 212 controls the broadcast reception chip 202 to receive a broadcast signal using the transmission mode and parameter information previously selected for the channel selected in the initial broadcast reception step performed in the broadcast viewing event occurrence . Here, the pre-selected channel may be a channel set in the digital broadcast receiver, a channel selected by the user, or a channel previously viewed by the user. In addition, the channel search controller 212 may prioritize the parameters to be transmitted in order of the frequently transmitted parameters, and search for the channels according to the priorities at the time of channel search.

The memory 220 stores various programs and data for the overall operation of the digital broadcasting receiver and includes a channel list storage unit 222 according to the present invention. And a channel list indicating the transmission mode and parameter information of each channel are received and stored. At this time, the channel list stored in the channel list storage unit 222 may be updated by full scanning or fast scanning.

The display unit 230 displays status information, numbers and characters, a large amount of moving images and still images generated during operation of the digital broadcasting receiver. In particular, the display unit 230 displays broadcast data or a searched broadcast channel list under the control of the controller 210. [

The input unit 240 includes a plurality of numeric keys, character keys, and function keys, and provides key input data corresponding to a key pressed by the user to the control unit 210. Particularly, according to the present invention, the input unit 240 receives a broadcasting viewing event and a broadcasting viewing channel, and provides the received broadcasting viewing channel to the controller 210.

FIG. 3 illustrates an operation procedure of a digital broadcast receiver according to an embodiment of the present invention.

Referring to FIG. 3, if the digital broadcasting receiver detects a power-on event in step 301, the digital broadcasting receiver proceeds to step 303 and performs a boot process to initialize and perform full scanning to search for a broadcast channel. That is, the digital broadcasting receiver performs scanning while changing a transmission mode for each of all broadcast channels during the booting process, thereby searching for a channel in which a broadcasting signal exists, and a transmission mode and a transmission parameter of the corresponding channel. At this time, the full scanning may be performed in a background mode so that the user can not recognize the full scanning. In step 305, the digital broadcasting receiver generates and stores a channel list indicating transmission modes and transmission parameters of a channel in which the broadcast signal exists and a corresponding channel.

Then, the digital broadcasting receiver checks in step 307 whether a broadcast viewing event occurs. If the broadcast viewing event is not generated, the digital broadcast receiver updates the channel list by performing fast scanning based on the channel list every predetermined period in step 319, and then returns to step 307. [

On the other hand, when the broadcast viewing event occurs, the digital broadcasting receiver performs synchronization on the selected channel in step 309 and receives a broadcast signal. That is, the digital broadcasting receiver confirms information on a transmission mode and a transmission parameter of a predetermined channel or a channel selected by the user in the channel list, and then synchronizes the channel with the selected channel using the information, .

In step 311, the digital broadcasting receiver measures the strength of the received signal and compares the strength of the received signal with a preset threshold value to check whether broadcasting is available. The digital broadcasting receiver displays a broadcast according to the received signal in step 321 when the broadcast is available, and if the broadcast is not available, proceeds to step 313 where the intensity of the received signal is zero or a second threshold Value is greater than or equal to the value of " If the strength of the received signal is 0, the digital broadcast receiving signal determines that there is no signal received in the channel. In step 317, the channel is changed, and the process returns to step 309.

On the other hand, if the strength of the received signal is equal to or greater than the second threshold, the digital broadcasting receiver determines that the status of the corresponding channel is improved, resynchronizes the corresponding channel in step 315, The process proceeds to step 321. [

If the strength of the received signal is greater than 0 but smaller than the second threshold value, the digital broadcasting receiver proceeds to step 323 where it performs full scanning to determine the channel in which the broadcasting signal exists, Parameters, and updates the channel list using the result of the full scanning in step 325, and then returns to step 309. In step 309, That is, the digital broadcasting receiver performs scanning while changing a transmission mode for each of all broadcasting channels to search for a transmission mode and transmission parameters of a channel in which a broadcasting signal exists and a corresponding channel, This is to prepare for the situation where the number is changed.

In the present invention, when the power of the digital broadcasting receiver is turned on, channels having broadcast signals are searched while changing transmission modes and parameters for all channels, and channel search is performed only on the searched channels in the idle state of the digital broadcasting receiver , It is possible to reduce the time required for the channel search. That is, as shown in FIG. 4, when performing the channel search method according to the present invention, it is possible to shorten the time 410 from channel search and acquisition.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

1 is a diagram illustrating an operation procedure of a digital broadcast receiver according to the related art,

2 is a block diagram of a digital broadcast receiver according to the present invention.

3 is a flowchart illustrating an operation procedure of a digital broadcast receiver according to an embodiment of the present invention, and FIG.

4 is a diagram illustrating a time required for channel search of a general digital broadcast receiver.

Claims (12)

A method for searching a broadcast channel in a digital multimedia broadcasting receiver, Performing channel search for all broadcast channels at power-on, Generating and storing a channel list including at least one of a transmission mode and transmission parameter information corresponding to the searched broadcasting channel, Performing a channel search based on at least one of a transmission mode and a transmission parameter for a broadcast channel included in the stored channel list when a channel search event is generated, Wherein the parameter information includes at least one of a number of subcarriers, a frame length, a guard interval length, an effective symbol length, and a null symbol length. The method according to claim 1, Wherein the step of performing channel search for all broadcast channels at the power- And determining a transmission mode for each broadcast channel while changing a plurality of transmission modes for all of the broadcast channels. 3. The method of claim 2, Wherein the determining of the transmission mode for each broadcast channel comprises: Calculating a maximum correlation value based on a Fast Fourier Transform (FFT) size and a length of a guard interval for each transmission mode for the searched broadcasting channel; And determining the transmission mode having the largest maximum correlation value as the transmission mode of the searched broadcast channel. The method according to claim 1, Wherein the step of performing channel search for all broadcast channels at the power- And performing a channel search for all the broadcast channels during a booting process of the digital broadcast receiver. 5. The method of claim 4, Checking whether or not an input by a user occurs when channel search for all the broadcast channels is not completed after booting of the digital broadcasting receiver is completed; If the input by the user is not generated, continues the channel search until the channel search for all the broadcast channels is completed, and stops the channel search if the input by the user occurs Further comprising: The method according to claim 1, Wherein the channel search event is periodically generated in an idle state of the digital broadcasting receiver, And updating the stored channel list based on a channel search result performed by generating the channel search event. A broadcast channel search apparatus in a digital multimedia broadcasting receiver, A control unit for controlling a function for performing a channel search on all broadcast channels when the power is turned on; Performs a channel search for all the broadcast channels under the control of the controller, generates a channel list including at least one of a transmission mode and transmission parameter information corresponding to the broadcast channel along with the broadcast channel searched by the channel search A communication module for performing a channel search based on at least one of a transmission mode and transmission parameters for a broadcast channel included in the channel list when a channel search event is generated; And a memory for storing the channel list, Wherein the parameter information includes at least one of a number of subcarriers, a frame length, a guard interval length, an effective symbol length, and a null symbol length. 8. The method of claim 7, Wherein the communication module determines a transmission mode for each broadcasting channel while changing a plurality of transmission modes for all the broadcasting channels when searching for a channel for all the broadcasting channels. 9. The method of claim 8, The communication module calculates a maximum correlation value based on a Fast Fourier Transform (FFT) size and a length of a guard interval for each of the transmission modes for the searched broadcasting channel, and transmits the transmission mode having the largest maximum correlation value to the searched broadcasting channel To determine a transmission mode of the mobile station. 9. The method of claim 8, Wherein the control unit controls the communication module to perform a channel search for all the broadcast channels during a booting process of the digital broadcast receiver. 11. The method of claim 10, The control unit checks whether or not an input by a user occurs when the channel search for all the broadcast channels is not completed after the booting of the digital broadcasting receiver is completed and if the input by the user does not occur And continues the channel search until the channel search for all the broadcast channels is completed, and stops the channel search if an input is made by the user. 8. The method of claim 7, Wherein the channel search event is periodically generated in an idle state of the digital broadcasting receiver, Wherein the controller updates the stored channel list based on a channel search result obtained by generating a channel search event.

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